Tampons as a source of exposure to metal(loid)s

Abstract

Background: Between 52-86% of people who menstruate in the United States use tampons-cotton and/or rayon/viscose 'plugs'-to absorb menstrual blood in the vagina. Tampons may contain metals from agricultural or manufacturing processes, which could be absorbed by the vagina's highly absorptive tissue, resulting in systemic exposure. To our knowledge, no previous studies have measured metals in tampons.

Objectives: We evaluated the concentrations of 16 metal(loid)s in 30 tampons from 14 tampon brands and 18 product lines and compared the concentrations by tampon characteristics.

Methods: About 0.2 - 0.3 g from each tampon (n = 60 samples) were microwave-acid digested and analyzed by inductively coupled plasma mass spectrometry (ICP-MS) to determine concentrations of arsenic, barium, calcium, cadmium, cobalt, chromium, copper, iron, manganese, mercury, nickel, lead, selenium, strontium, vanadium, and zinc. We compared concentrations by several tampon characteristics (region of purchase, organic material, brand type) using median quantile mixed models.

Results: We found measurable concentrations of all 16 metals assessed. We detected concentrations of several toxic metals, including elevated mean concentrations of lead (geometric mean [GM] = 120 ng/g), cadmium (GM = 6.74 ng/g), and arsenic (GM = 2.56 ng/g). Metal concentrations differed by region of tampon purchase (US versus European Union/United Kingdom), by organic versus non-organic material, and for store- versus name-brand tampons. Most metals differed by organic status; lead concentrations were higher in non-organic tampons while arsenic was higher in organic tampons. No categoriy had consistently lower concentrations of all or most metals.

Discussion: Tampon use is a potential source of metal exposure. We detected all 16 metals in at least one sampled tampon, including some toxic metals like lead that has no "safe" exposure level. Future research is needed to replicate our findings and determine whether metals can leach out of tampons and cross the vaginal epithelium into systemic circulation.

Keywords: Environmental Exposure; Menstrual Hygiene Products; Menstruation; Metals; Vaginal Absorption.

Fig. 1.

A tampon separated into its components, including the (A) non-woven outer covering, (B) withdrawal string, (C) inner absorbent core, (D) applicator, and (E) wrapper.

Fig. 2.

Boxplots of metal distributions in tampon samples (n = 60). Machine read values were used for metal concentrations below the MDL; please note that 54/60 (90 %) of Cr and 55/60 (91.7 %) of Hg in tampon samples were below the MDL. The figure is split into three panels for visualization purposes only.

Fig. 3.

Correlation matrix of metals analyzed in 60 tampon samples. Machine read values were used for sample concentrations below the MDL; please note that 54/60 (90%) of Cr and 55/60 (91.7%) of Hg were below MDL in tampons. Darker red corresponds to a negative correlation, while darker blue corresponds to a positive correlation. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)

Fig. 4.

Comparison of metal concentrations in organic (yellow) versus non-organic (green) tampons, n = 58. We did not have information on organic status for two tampon samples (one product) due to packaging loss. *Significant difference after running median quantile regression. Machine read values were used for sample concentrations below the MDL. Please note that 52/58 (90 %) of Cr and 55/60 (91.7 %) of Hg samples were below the MDL. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of this article.)